Researchers have used two quantum computers and two supercomputers to simulate a molecule with 12,635 atoms, breaking the previous record. The hybrid approach targeted protein-ligand complexes relevant to drug discovery. The achievement marks progress toward practical quantum simulations despite current hardware limitations.
A team from the Cleveland Clinic, IBM, and RIKEN developed a hybrid method combining quantum and classical computing to model unprecedentedly large molecules. They simulated two protein-ligand complexes, one about 40 times larger than the prior quantum simulation record, immersed in a water layer to mimic lab conditions. The effort used IBM Heron quantum computers at RIKEN and the Cleveland Clinic, alongside the Fugaku and Miyabi-G supercomputers, over more than 100 hours of back-and-forth calculations. Quantum hardware handled specific fragment properties, with supercomputers processing the outputs. Team member Kenneth Merz at the Cleveland Clinic called it a personal dream realized. The simulations estimated molecular energies with accuracy matching some standard methods, and the process was reportedly faster than without quantum aid, according to IBM's Jerry Chow. Chow described it as an initial step in pushing quantum capabilities, stating, “There’s this groundswell of just pushing the envelope of what can be done.” Junyu Liu at the University of Pittsburgh praised the scale as “genuinely impressive” and highlighted practical steps for current hardware. He noted the approach could make quantum computers useful pre-error-proofing, though mathematical proof of quantum advantage remains unresolved. The work appears in arXiv:2605.01138.